Opera and Netscape browsers allow you to include java methods calls in your=
=20
javascript .
As Javascript has support for objects you can use objects returned by=20
these calls in your scripts .

I have been looking for information about the possibly security=20
implications ( and vulnerabilities
published ) that this could have , but have found nothing . Doing some test=
=20
by myself this is what
I have found .

Opera 6.01

If you use Opera 6.01 you can make calls to Java exec function , which=20
executes the command
line passed to it . This means you can execute any program . Here is a=20
small demonstration

http://usuarios.lycos.es/idoru/petaopera.html

The second link executes windows calculator . The first link executes=20
verifier.exe , a W2000/XP
program , causing a buffer overflow in it ( W2000 server is full of command=
=20
line buffer overflows ),
this means that just visiting a webpage ( a malicious site or a post in a=20
forum ) code can be
executed in your machine with user priviliges .

Besides , playing with sockets from javascript you can obtain the local Ip=
=20
address with

var host=3Djava.net.InetAddress.getLocalHost();

and use it to connect to an arbitrary local tcp port on your IP . If you=20
are connected to a LAN ,
you can connect with every socket in your LAN interface.This means that=20
with viewing some
post in a forum , a script can connect to a port on your PC and send and=20
recieve data ( as
classes like InputDataStram can be used as well ). A new type of cross site=
=20
scripting focused
in exploiting vulnerable services .

An example can be found here , connection to port 139 can be tracked with=20
netstat ( before
closing the browser )

http://usuarios.lycos.es/idoru/sockets.html


Opera 7.02 and Netscape 7.02

Both browsers don=B4t allow to make java calls to determinate methods . Well=
=20
, are allowed
by they return a null . You can`t execute exec or delete , just methods=20
like java.io.File.exists()
or java.io.File.list() but you can still execute sockets .

Fourtunately , I wasn=B4t able of retriving another IP different from=20
localhost when the script is
executed in the server , but it works fine if you email the webpage ,=20
establishing the connection
with port 139 . I don=B4t know if there is an alternative method of=20
retrieving a visitor's IP address from
java or javascript but if there is this can be exploitable via cross site=20
scripting .

Email sockets.html to you or open it locally and you will see a connection=
=20
with netstat .



Regards ,

David F.Madrid ,
Madrid , Spain=20